Agricultural equipment, such as a tractor or a self-propelled combine-harvester, includes a prime mover which generates power to perform work. In the case of a tractor, the prime mover is gas powered engine or a diesel engine that generates power from a supply of fuel. The engine drives a transmission which moves wheels or treads to propel the tractor across a field. In addition to providing power to wheels through a transmission, tractors often include a power takeoff (PTO) which includes a shaft coupled to the transmission and which is driven by the engine.
In both gas powered and diesel powered engines, the amount of work performed not only includes moving the vehicle along a road or field, but delivering power to a wide variety of accessories driven the engine and often by the PTO. The PTO of agricultural equipment drives what is known as work machines, also known as performance systems which include but are not limited to: farm implements or attachments, discs, spreaders, combines, or balers. Some work vehicles include a hydraulic machine having a hydraulic pump which can be used, for instance, to raise or lower a piece of equipment such as a mower. In other embodiments, the PTO can be coupled to a number of different types of equipment, including but not limited to log splitters, pumps, concrete mixers, mulchers, chippers, balers, harvesters, spreaders, and sprayers.
Work machines, including many agricultural work machines such as balers, are known to use a single drive source to power multiple performance systems each designed to accomplish a task within the overall function of the machine. The performance systems may require periodic maintenance or adjustment for proper operation. Performing the maintenance or adjustment procedure often requires precise positioning of the parts in the performance system and/or advancing the parts through an operating cycle of the system in a slow, controlled manner for observation of the operation of individual components.
The torque provided by the engine of a tractor, for instance, is directed to the work machine through a work machine drive train operatively connected to the PTO of the tractor. The machine drive train in a baler, for instance, includes a flywheel, which is used to store rotational energy delivered by the PTO. The amount of energy stored in the flywheel results from the weight of the flywheel as well as the rotational speed at which the flywheel operates. In one embodiment of a flywheel located in the baler, the amount of horsepower provided by the flywheel can be 1000 horsepower, which provides a large amount of rotational power, or torque. While rotational control of the flywheel in the baler during a baling operation is important to maintaining control of the baling process, it is also important to be able to adjust the position of the flywheel when the performance system needs maintenance, repair, or fails other reasons.
One performance system in the baler is a knotter system which guides twine around a bale being formed, ties the twine, and cuts the twine to complete the bale. It is recommended that various components in the knotter system be adjusted for optimum performance. As part of the adjustment or maintenance function, it can be necessary to first move parts of the knotter system to certain positions for adjustment, and then to rotate the system through a full operating cycle to observe the positions and operations of the components during the performance cycle. For example, when adjusting a needle protection linkage in a baler knotter system, the baler flywheel is moved to a precise position for adjusting the needle protection linkage. Once adjusted, a complete operating cycle of the knotter system is made to observe that the protection linkage gap is properly set. Similar procedures are followed for making adjustments to other components of the knotter system, such as the tucker arms, twine fingers and needles.
Under some circumstances, baling operations can fail if the amount of cut crop becomes excessive in the baling chamber or if a foreign object, such as a large rock, enters the baling chamber and interferes with the baling operation. In each of these situations, the flywheel can continue to move, but becomes disconnected from the PTO driven drive train, through the action of a clutch mechanism. Consequently, the final resting location of the flywheel can be at a position which is not conducive to removal of the obstruction or for eliminating the condition which has caused the baler to malfunction.
Balers, therefore, include a secondary drive mechanism to operate the drive system, including the flywheel, at a controllable reduced rate of speed. The flywheel, and therefore, the gear train driving the baler mechanism, are moved to or positioned at a location to allow the offending obstruction to be removed or the malfunction causing condition to be remedied. Such secondary drive systems are often driven by a drive belt having a belt tension which needs to be adjustably controlled for proper operation. In these systems, the tension is adjusted by a manual engagement lever which tightens the drive belt to a tension determined by an operator. Manual tightening of drive belt is, however, not an accurate process and often requires multiples attempts at tightening by an operator to determine the proper tension. If the tension is not correctly set, locating the flywheel at the required location can require multiple attempts to find the correct location. What is needed, therefore, is an idler system for a work machine which not only provides for accurate control of a flywheel location during periods of machine adjustment, maintenance, or repair, but also enables an operator to accurately control the location of the flywheel and therefore the drive system.